Newbie Questions about file sizes and DVD disc sizes

[pixel_a_ted]

I've converted some old family VHS tapes to MP4 files and am now ready to write some DVD's. I am going to use iDVD as it's available on my MacBook Pro - I did a test using a couple of small files and the DVD that I created worked on my Blu-Ray player. I should mention also that I used iMovie and it didn't allow saving the MP4's in 4:3 format, so I saved in the lowest 16:9 format, cropping to fit (so black borders on left and right).

I have about 10 files, almost 18 GB total, varying in size from about 500 MB to about 2 GB. What I am trying to understand is how to group these files onto the smallest number of DVD's.

What is the relationship between total GB of files that I group together and the 4.7 GB capacity of the disk? Do I have to keep each group of files under 4.7 GB or can more be written due to use of compression by iDVD? As these videos came from VHS tapes made with older camcorders (some tapes were over 25 years old) there is no point shooting for the highest quality.

Or should I be looking at the time duration of each file? Any suggestions would be appreciated.

Thank you.

[redwudz]

Single layer DVDs actually hold 4.37GB of data. You can reduce the size of the files during the encodes. Time of the clips doesn't really matter, just size. Smaller size, lower quality.
For more information about DVD specifications, formats and structure, look to the upper left on this page for 'WHAT IS' DVD.

And pixel_a_ted, in the future please use a more descriptive subject title in your posts to allow others to search for similar topics. I will change yours this time. From our rules:

Try to choose a subject that describes your topic.
Please do not use topic subjects like Help me!!! or Problems.

Thanks,

Moderator redwudz

[videobruger]

What is the relationship between total GB of files that I group together and the 4.7 GB capacity of the disk?

None - unless the files are already encoded to be DVD compliant.

Or should I be looking at the time duration of each file?

Yes.

The maximum bitrate that can be used on a DVD is 9.8 Mb/s for the video and 10.08 Mb/s for video+audio.

You have

Size = Playtime * Bitrate

so for a 4.7 GB disc for playtime below an hour you can use the max bitrate and start lowering it when the playtime exceeds an hour. How much playtime you can squeeze onto a DVD with acceptable quality is for you to decide but I would say 2-3 hrs.

[pixel_a_ted]

[QUOTE=videobruger;2459573]

How much playtime you can squeeze onto a DVD with acceptable quality is for you to decide but I would say 2-3 hrs.

Yes, for me to decide, but I was after guidance from you more experienced people based on the fact that these are low quality videos from early camcorders.

The MP4's I saved appear to be about 25 minutes in duration for every GB of file size. So using your estimate of 2.5 hours, that would correspond to 6 GB worth of MP4's written to each DVD. I've so far only used the most rudimentary features of iDVD but assume somewhere in there I can adjust bitrates. And that's useful to know, if I'm understanding correctly, that I could possibly write 6 GB of my files onto a single DVD.

[jagabo]

Once you go over an hour you will start losing quality. DVDs are cheap. Why bother putting more than an hour on each disc? Unless these are movies you're never going to watch more than that at one time anyway.

[pixel_a_ted]

Once you go over an hour you will start losing quality.

That's what I'm trying to understand - testing various scenarios would be very time consuming as it takes a long time to process and write these files using iDVD.

Again, these are low quality, early camcorder standard definition videos. While going over an hour might introduce a noticeable quality difference with an HD video, would it be noticeable with the videos I have, considering what they are to start with?

[jagabo]

Again, these are low quality, early camcorder standard definition videos.

All the more reason not to degrade them any further.

While going over an hour might introduce a noticeable quality difference with an HD video, would it be noticeable with the videos I have, considering what they are to start with?

DVD is always SD. Going a little over an hour might not be noticeable. But 2 hours or definitely will.

If you're going to attempt more than 2 hours be sure to drop the resolution to 1/2 D1 (352x480 NTSC, 352x480 PAL). The loss of resolution will hardly be noticeable with a VHS source. But you'll get a lot less blocking and posterization.

[JVRaines]

I've converted some old family VHS tapes to MP4 files …

Why not just share the MP4 files with family and friends? Make them accessible in the cloud somewhere. Put them on flash drives for people who know how to play video on their computers and/or video systems. DVD is a dying standard, plus you will have a quality loss re-encoding to MPEG-2.

[jagabo]

You can also just write your MP4 files to DVDs as data files. They won't play in standard DVD players but many Blu-ray players may be able to play the files (depending on the codecs). And, of course, people can just copy the files off the DVDs to their computers if they have a DVD drive.

[pixel_a_ted]

I was planning to share the MP4's as well. I got involved with DVD's with the idea of using m-discs as a long-term archiving method. I know, it assumes that readers will be available, but since I was able to read > 25 year old VHS tapes with two VCR's that I still have, I am guessing the discs can be read 10-15 years in the future. At that point, we can convert them to 3-d holographic memory cubes, or whatever the new technology will be.

[pixel_a_ted]

Going a little over an hour might not be noticeable. But 2 hours or definitely will.

As a followup, I still have a bit of confusion here. First, I wrote the MP4's to DVD's (5 in total) as suggested, but I would still like to make some DVD's that can be played in our Blu-Ray player (as a test DVD showed was possible).

The MP4 videos that I have are all about 25 minutes of video for each GB of file size. Assuming 4.3 GB available on the DVD (ignoring for now space taken up by menus), doesn't that mean that I could write about 1 hour 48 minutes of video without any quality-reducing compression/encoding?

[jagabo]

I would still like to make some DVD's that can be played in our Blu-Ray player (as a test DVD showed was possible).

The MP4 videos that I have are all about 25 minutes of video for each GB of file size. Assuming 4.3 GB available on the DVD (ignoring for now space taken up by menus), doesn't that mean that I could write about 1 hour 48 minutes of video without any quality-reducing compression/encoding?

Not unless your videos are already compressed with DVD compatible MPEG 2 video and DVD compatible audio so that they can simply be remuxed into VOB files. Otherwise they have to be reencoded will which will result in loss of quality. MPEG 2 does not compress as well as some other codecs, like MPEG 4 part 10 (h.264) or MPEG 4 part 2 (Divx/Xvid).

[pixel_a_ted]

Thank you. Obviously this is a subject beyond my current knowledge - and more than I want to get into now since this is likely a one off task for me - so some trial and error encoding is in order.

[pixel_a_ted]

Just to complete the story - I used iDVD to create four DVD's for my 17.5 GB worth of MP4's. When I brought each set of about 4.3 GB files into iDVD I got a message that because of the total file size I would have to change the encoding from the default Best Performance. The other choices, High Quality and Professional Quality were confusing, but I went with the latter (to be more professional ). I followed suggestions I had read and created disc images first, which I could check with Apple's DVD Player program, and later burned them to m-discs. I have to say that in comparing the quality from the DVD's using DVD Player against that of the original MP4 files viewed in Quicktime Player, I could see no difference even when expanding the viewing window to almost all of my 24" monitor. The DVD's play on my Panasonic Blu-Ray player. So all in all I am satisfied and this long project appears to finally be over. Thanks for all the help/advice.